In prior-art portable electronic devices, touch screens are used to replace the mouse and the keypad, for example. The user issues commands to the device by touching objects visible on the touch screen. The use of the touch screen lock state, such as a screensaver state, is known in devices having a touch screen, such as mobile stations having touch screens, to prevent the operation of the device when the touch screen is inadvertently touched for instance during transport or by the user. The touch screen can be locked for instance by depressing a key or keys in the keypad or by selecting said function using the menus on the touch screen. It is also usual for the touch screen to automatically enter a so-called screen saving state when the device is not used for a given time. When in the screen saving state, the touch screen may show so-called screen saver information, such as news reviews via an Internet connection. The screen saving state ends when the user touches the screen or the keypad or moves the mouse, for example. However, to prevent unauthorized use of the device, a special screensaver password may be taken into use, for example, and the user has to enter it for instance via the keypad to deactivate the screensaver state.
The drawback in prior art solutions is the difficulty in remembering special screensaver passwords. In addition, the use of screensaver passwords is especially hard for certain user groups, such as the elderly and handicapped. Furthermore, when for instance a person who is authorized to use the device but is not the person who specified the screensaver password wants to use the device, he has to know the password. If, again, no screensaver password is required to deactivate the screensaver state, the device may be subjected to unauthorized use or be activated unintentionally during transport, for example. Further, a separate input device, such as a keypad or a writing pad, is required for inputting screen save passwords, which complicates the use of a device having a touch screen.